Mapel Xena Marie, Hiltpold Maya, Kadri Naveen Kumar, Witschi Ulrich, Pausch Hubert
Animal Genomics, ETH Zürich, Universitätsstrasse 2, 8006 Zürich, Switzerland.
Swissgenetics, Meielenfeldweg 12, 3052 Zollikofen, Switzerland.
JDS Commun. 2022 Jan 10;3(2):120-125. doi: 10.3168/jdsc.2021-0164. eCollection 2022 Mar.
Undisturbed reproduction is key for successful breeding of beef and dairy cattle. Improving reproductive ability can be difficult because of antagonistic relationships with other economically relevant traits. In cattle, thorough investigation of female fertility revealed unfavorable genetic correlations with various production phenotypes. However, the correlation between male reproductive ability and production traits remains poorly understood. Here, we investigated the genetic relationships among and between male fertility characteristics and economically relevant traits in a population of Brown Swiss cattle. We performed GWAS with imputed genotypes at nearly 12 million sequence variants for semen quality (sperm head and tail anomalies, motility, concentration, and volume), male fertility, and 57 production phenotypes. Allele substitution effects were then correlated on a trait-by-trait basis to estimate genetic correlations. Correlations between male reproductive characteristics and traits of economic value were small and ranged from -0.0681 to 0.0787. Among the semen quality parameters, sperm motility was negatively correlated with anomalies (head: r = -0.7083 ± 0.0002; tail: r = -0.7739 ± 0.0002) and volume (r = -0.1266 ± 0.0003), whereas volume was negatively correlated with concentration (r = -0.3503 ± 0.0002). Sire nonreturn rate was negatively correlated with sperm anomalies (head: r = -0.1640 ± 0.0002; tail: r = -0.1580 ± 0.0002) and positively correlated with motility (r = 0.1598 ± 0.0002). A meta-analysis of male reproductive traits identified 2 quantitative trait loci: a previously described region on chromosome 6 showed pleiotropic effects and a novel region on chromosome 11 was associated with sperm head anomalies. In conclusion, our results suggest that selection for economically important dairy and production phenotypes has little impact on semen quality and fertility of Brown Swiss bulls.
不受干扰的繁殖是肉牛和奶牛成功育种的关键。由于与其他经济相关性状存在拮抗关系，提高繁殖能力可能会很困难。在牛群中，对雌性生育能力的深入研究揭示了其与各种生产表型之间存在不利的遗传相关性。然而，雄性繁殖能力与生产性状之间的相关性仍知之甚少。在此，我们研究了瑞士褐牛群体中雄性生育特征与经济相关性状之间的遗传关系。我们对近1200万个序列变异的推算基因型进行了全基因组关联研究（GWAS），涉及精液质量（精子头部和尾部异常、活力、浓度和体积）、雄性生育能力以及57种生产表型。然后，基于逐个性状的基础上对等位基因替代效应进行关联分析，以估计遗传相关性。雄性繁殖特征与经济价值性状之间的相关性较小，范围在-0.0681至0.0787之间。在精液质量参数中，精子活力与异常（头部：r = -0.7083 ± 0.0002；尾部：r = -0.7739 ± 0.0002）和体积（r = -0.1266 ± 0.0003）呈负相关，而体积与浓度呈负相关（r = -0.3503 ± 0.0002）。种公牛不返情率与精子异常（头部：r = -0.1640 ± 0.0002；尾部：r = -0.1580 ± 0.0002）呈负相关，与活力呈正相关（r = 0.1598 ± 0.0002）。对雄性繁殖性状的荟萃分析确定了2个数量性状位点：先前在6号染色体上描述的区域显示出多效性效应，11号染色体上的一个新区域与精子头部异常有关。总之，我们的结果表明，选择具有经济重要性的奶牛和生产表型对瑞士褐牛种公牛的精液质量和生育能力影响很小。
